What is really remarkable about Herper’s article is how quickly the oncology field is changing. The search for drugs over the last decade or so has focused on disrupting tumor biology through targeted therapies modeled after ’ small-molecule blockbuster Gleevec for CML, or monoclonal antibodies like Herceptin for breast cancer. This approach is reflected in the nearly 50% market share captured by targeted drugs in the world’s largest oncology markets.

Healthy Human T Cell (Photo credit: NIAID)

When successful, this approach can work wonders, but most cancers are far more complex than CML, which has just a single mutant gene. Inevitably, at least a fraction of patients treated with targeted drugs (assuming they respond at all) will develop drug resistance as tumor cells mutate to utilize other growth-promoting pathways. Like our own, cancer’s biology is both resilient and deeply redundant.

Rather than trying to unravel the Gordian knot of tumor biology, new immunotherapies harness the body’s own immune system to attack and kill cancer cells. In a nutshell, the latest cancer immune therapies strip away the “camouflage” cancer cells use to evade the body’s immune system.

As the editors of Science noted when they declared cancer immunotherapies the breakthrough of the year,

“The field hums with stories of lives extended: the woman with a grapefruit-size tumor in her lung from melanoma, alive and healthy 13 years later; the 6-year-old near death from leukemia, now in third grade and in remission; the man with metastatic kidney cancer whose disease continued fading away even after treatment stopped.”

The high cost of current cancer therapies is at least limited by the relatively small patient populations they treat. generation immunotherapies, including CTLA-4, PD-1 (programmed cell death), and chimeric antigen receptor therapies (CARTs), appear to deliver much improved outcomes (in some cases including complete remissions) with limited side effects – and may also be used to treat many more cancer types and much larger patient populations than current therapies. Given their inherent value to patients, they could easily command prices well in excess of $100,000 per course of treatment.

Researchers have known since the late 19th century that the immune system could help fight cancer, after a surgeon at Memorial Hospital in New York noticed that some bone cancer patients had better outcomes when they developed bacterial infections after surgery.

In a sense, the highest of high-tech medicine is returning to its barnyard roots in Edward Jenner and Louis Pasteur. The first drugs were vaccines, passed from arm to arm via scab scrapings that carried the cow pox virus across continents and oceans. Vaccine pioneers basically learned how to harness our immune system – evolved over hundreds of thousands of years – to churn out defenders (anti-bodies) to wipe out smallpox, cholera, diphtheria, and dozens of other diseases that had ravaged human civilization since the first agricultural communities brought large numbers of humans together in close confines.

Indeed, one vaccinologist, Maurice Hilleman at , is credited with saving more lives through the dozen or so vaccines he pioneered than any other scientist in history.

Modern cancer immunotherapies attack cancerous cells through a number of different applications, including monoclonal antibodies (which are already well characterized and widely used). The newest drugs go a step further, including drugs that “take the brakes off” the body’s immune system (Yervoy, for melanoma) to ramp up the number of circulating tumor-killing cells, or genetically re-engineering a patient’s own T-cells to attack the disease (the subject of Herper’s excellent article and another in the Wall Street Journal).

While true cancer vaccines have yet to find broad success (Provenge has had limited success, both with patients and in the market) a number of companies are still hard at work in the field.

Immune therapies offer a tantalizing glimpse of cancer’s future. While targeted and cytotoxic therapies will likely remain weapons in oncology’s arsenal for years or decades to come, they will be used alongside immune modulating therapies (and possibly even cancer vaccines) that can deliver lasting disease control. Over time, oncologists will likely personalize cancer therapies based on tumor genome sequencing and blood tests (for circulating tumor cells) that will allow them to track disease response and recurrence, and deliver precision cancer therapies to prevent metastatic disease from becoming life threatening.

But the fact remains that as immune-based therapies for cancer are developed and marketed, they may be used alongside already expensive targeted drugs. And payers are already struggling to fund impressive advances against Hepatitis C, multiple sclerosis, and rheumatoid arthritis, to name just a few other expensive specialty drug indications. In at least the short term, can society afford to win the war on cancer?